1. Field of the Invention
The present invention relates to an air conditioning system, and particularly, to an air conditioning system capable of controlling opening and closing of an electronic expansion valve even when power supplied into an indoor unit is blocked while driving the electronic expansion valve, and a method for controlling an operation thereof.
2. Background of the Invention
In general, an air conditioning system includes a compressor for compressing a refrigerant into a state of high temperature and high pressure, a condenser for heat exchanging the high-temperature and high-pressure refrigerant transferred from the compressor with ambient air so as to convert into a liquid state of low temperature and high pressure, an expansion valve for decompressing the refrigerant converted in the liquid state by the condenser into a liquid or gaseous state of low temperature and low pressure, an evaporator for maintaining a low external temperature by allowing the low-temperature and low-pressure refrigerant to flow therethrough, a blow fan for discharging the cooled air by the evaporator into a room, an accumulator for filtering the refrigerant in the liquid state from the refrigerant gas evaporated by the evaporator so as to be introduced back into the compressor, and a controller for controlling an entire operation of the air conditioning system.
Meanwhile, the air conditioning system may be classified according to the type and the number of components, such as an indoor unit, an outdoor unit, a controller, a connection pipe and the like. Namely, a rotary air conditioner may be composed of one indoor unit and one outdoor unit, a unitary air conditioner may be provided with one outdoor unit, one or more indoor units and a duct, and a multi air conditioner may be comprised of one or more outdoor units, one or more indoor units and a central control unit.
An air conditioning system may typically include a compressor and a condenser within an outdoor unit, and an evaporator, a blow fan and a controller within an indoor unit. The indoor unit may perform air conditioning of each room (chamber), and the outdoor unit may monitor state information relating to an indoor unit connected thereto so as to control a refrigerant to be distributed and circulated into the connected indoor unit. The air conditioning system may consume considerable power, due to its characteristic of performing the air conditioning by circulating the refrigerant, as compared to other home alliances, thereby increasing the burden on maintenance cost.
However, regarding the indoor unit of the air conditioning system and a method of controlling the operation thereof according to the related art, the controller, which has been supplied with a voltage of 12V from a power supply unit, typically outputs a driving signal to open and close the electronic expansion valve. If the power supplied into the indoor unit is blocked while the controller controls opening and closing of the electronic expansion valve, the electronic expansion valve may problematically be left open.
Also, if the electronic expansion valve is left open, a refrigerant pipe remains in an open state and the compressor of the outdoor unit is converted into an overload state, which may cause the air conditioning system to be out of order.